Method of operating metallurgical furnaces



y 7, 1970 w. FADLER METHOD OF OPERATING METALLURGICAL FURNACES OriginalFiled Feb. 20, 1967 2 Sheets-Sheet 1 INVENTOR M4176? M0452 018aATTORNEYS July 7, 1970 w. FADLER 3,519,719

METHOD OF OPERATING METALLURGICAL FURNACES Original Filed Feb. 20, 19672 Sheets-Sheet 2- l NV ENTOR Mil-T62 FAmee ATTORNEYS United StatesPatent 3,519,719 METHOD OF OPERATING METALLURGICAL FURNACES WalterFadler, Vienna, Austria, assiguor to Wiener SchwachstromwerkeGesellschaft m.b.H., Vienna, Austria Original application Feb. 20, 1967,Ser. No. 617,396. Divided and this application Nov. 21, 1968, Ser. No.792,184 Claims priority, application Austria, Feb. 22, 1966, A 1,608/66Int. Cl. H05b 5/00 US. Cl. 13-34 1 Claim ABSTRACT OF THE DISCLOSURE Amethod of operating a barrel-type, metallurgical induction furnace byrotating it so that a selected one of two induction heaters extendsupwardly above the melt while the other extends downwardly from belowthe bottom of the furnace. The downwardly extending induction heateroperates to heat the material inthe furnace whereas the upper one isswitched off. In the event the lowermost heater is to be replaced orallowed to be switched off for a period of time, the barrel-type furnaceis rotated to a second position in which the heater positions arereversed.

This application is a division of application Ser. No. 617,396, filedFeb. 20, 1967.

This invention relates, in general, to the method of operatingmetallurgical furnaces and, in particular, to a new and usefulbarrel-type furnace constructed and arranged so that it may be orientedwith selected one of two inductive heaters in an effective position andwith the other of the heaters positioned to permit replacement thereof.

The durability of the lining of a furnace depends principally on thewall thickness of the lining. In the case of induction furnaces whichinclude crucible inductors which are secured to the furnace vessel, thelining of the crucible inductors must necessarily be thinner than thelining of the furnace vessel in order to minimize the stray field. As aresult, the crucible inductors do not last for the life of the furnaceand they must be frequently replaced. It is important that thereplacement of the inductors be carried out as quickly as possible inorder that the operation of the furnace be not unduly interrupted and inorder to insure that the temperature does not drop inside the furnace bya considerable amount.

In accordance with the invention, there is provided a barrel-typeinduction furnace which is mounted so that it may be rotated anddisposed in either a first position with a first inductive heaterarranged at the lowermost end thereof in an operative position andsecond inductive heater arranged in an uppermost position at aninoperative location or it may be rotated to a second position in whichthe inductive heater positions are reversed. In the preferredarrangement, the inductive heaters are formed as lateral extensions ofthe barrel-type furnace and they are arranged in diametrically oppositeextensions formed on the furnace. The extensions provide a mounting fora replaceable crucible inductor which will be oriented in the samemanner as the extensions with their axes inclined in respect to thecentral axis of the barrel furnace. The induction heaters are alsoadvantageously arranged symmetrically to the central axis of the barrelfurnace.

During operation of the furnace, the furnace is oriented so that one ofthe induction heaters extends upwardly above the surface of the meltwhereas the other one extends downwardly from below the bottom of thefurnace.

p ICC The downwardly extending induction heater would be in an operativeposition to heat the material in the furnace and the upper one of theinduction heaters would be switched off. In the event that the lowermostheater must be replaced or be allowed to be turned off for a period oftime, it is merely necessary to rotate the barrel-type furnace in orderto position the opposite heater in an operative position at which itextends downwardly from the bottom of the furnace. When this is done,the other one is automatically positioned in an uppermost position atwhich it may be turned off and left inoperative. In this inoperativeposition, it may be removed and the extension portion of the furnace maybe plugged if desired, or the defective induction heater may be replacedby a new induction heater.

In accordance with a further feature of the invention, the barrel-typefurnace includes two diametrically opposite pouring spouts. One of thespouts arranged on one side of the furnace defines a passage which willextend upwardly when the other spout defined on the opposite side of thefurnace has the passage defined thereby turned downwardly. Duringoperation, the downwardly turned spout may be plugged and the upwardlyturned spout may be used for pouring 01f the melt by tilting the furnacein a direction to move the discharge end thereof downwardly below thelevel of the melt. In addition, it is a simple matter to plug either orboth of the spout passages to permit complete rotation of thebarrel-type furnace where desired.

Accordingly, it is an object of the invention to provide an improvedbarrel-type furnace which includes a tubular furnace member which ismounted to be rotated between a first position and a second position andwhich includes inductors which are arranged at diametrically oppositelyextending sides, one of which will be positioned uppermost in the firstposition of the barrel furnace and the other of which will be positionedlowermost, the barrel being rotatable to change the position of theinductors in the second position to permit replacement or removalthereof or operation thereof as desired.

A further object of the invention is to provide a rotatable barrel-typefurnace which includes a plurality of inductor heaters which may beselectively moved between an operative and an inoperative position inorder to permit the inductors to be either used to heat the melt orshut-off and either replaced or removed as desired.

A further object of the invention is to provide a metallurgical furnacewhich is of barrel configuration and is mounted for rotation and whichincludes spout members formed at diametrical sides, with one of thespout members defining a downwardly extending passage and the other ofthe spout members defining an upwardly extending passage, the spout withthe downwardly extending passage being adapted to be plugged to permitthe other passage to be used for pouring the melt or both of thepassages being adapted to be plugged to permit rotation of the barrelfurnace.

A further object of the invention is to provide a metallurgical furnacewhich is simple in design, rugged in construction and economical tomanufacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

In the drawings:

FIG. 1 is a longitudinal sectional view of a barrel furnace constructedin accordance with the invention;

FIG. 2 is a section taken on the line 2-2 of FIG. 1; and

FIG. 3 is a view similar to FIG. 2 indicating the barrel furnace in arotated position.

Referring to the drawings in particular, the invention embodied thereincomprises a metallurgical furnace including a barrel-type furnace vesselgenerally designated 1 which is rotatably supported on a pedestal 10.

In accordance with the invention, the barrel-type furnace includesdiametrically oppositely formed extension portions 12 and 14 which areprovided for mounting crucible inductors 4 and 3, respectively. Duringoperation of the furnace, one of the inductors, that is, the inductor 3in the drawing, is disposed in an operative position below the bathsurface 5 to provide a means for heating the melt. A feature of theconstruction is that the opposite inductor, the inductor 4, is disposedin a position above the melt surface 5 so that it can be removed fromthe furnace and replaced if desired.

In the event that it is desired to discontinue the operation of theinductor 3, then the furnace is rotated from the position indicated inFIG. 1 to cause the inductors 3 and 4 to be positioned in the dottedline position indicated at 3 and 4'. The rotation takes place about thecenter line 2. After the rotation is completed, the inductor 3 will bein the position 3' so that it can be either removed and replaced or theextension 14 can be plugged to permit operation only with the inductor4. In the event that it is decided to remove an inductor and to plug theextension, it is usually advisable to provide a cover construction whichis water-cooled in order to avoid any loss of heat by radiation.

A further feature of the invention is indicated in respect to theshowings of FIGS. 2 and 3. The barrel-type furnace of the inventionincludes a spout formation 16 on its one side with an upwardly directedpassage 6 and a spout formation 17 on its opposite side with adownwardly directed passage 7. As indicated in the drawing, the passage7 is plugged at the opposite end by tightly securing at the dischargeend a plug or stopper member 8. In the operating condition indicated inFIG. 2, the tapping duct 6 may be employed for tapping the melt 3. Toaccom- 4 plish this, the furnace 1 is rotated in the direction of thearrow 9 to bring the passage discharge end down below the surface of themelt 5 and to cause the outpouring of the melt material.

In order to permit the furnace to be rotated such as for the replacementof an inductor, the ends of each of the passages 6 and 7 are pluggedwith suitable plugs as indicated in FIG. 3.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. A method of operating a barrel-type furnace which comprises a furnacevessel which is rotatable about its axis and includes a crucibleinductor extending downwardly from one end and upwardly from an oppositeend comprising operating the furnace with the downwardly extendinginductor turned on and continuing the operation thereof until theinductor requires deenergizing, and rotating the furnace to position thedownwardly extending inductor in an upwardly extending position and theupwardly extending inductor in a downwardly extending position andthereafter operating the furnace with the downwardly extending inductorenergized.

References Cited UNITED STATES PATENTS 1,094,354 4/1914 Wilmowsky l3-102,406,147 8/1946 Hopkins 1310 2,754,346 7/1956 Williams 13-6 X 3,088,1826/1963 Tama et al. 26633 3,244,495 4/1966 Apple et al. 13-6 X BERNARD A.GILHEANY, Primary Examiner H. B. GILSON, Assistant Examiner US. Cl. X.R.

